The present invention relates to gas conditioning for an electrostatic precipitator and in particular to on-site equipment for converting sulfur into sulfur trioxide.
Known electrostatic precipitators work most efficiently when the gas being treated has an appropriate resistivity. It is known to alter the resistivity of the gas being treated by injecting sulfur trioxide (SO.sub.3). A disadvantage with this procedure is the difficulty in handling SO.sub.3, a highly corrosive substance. For this reason, known practical gas conditioning devices have often produced the SO.sub.3 on site by means of a sulfur burner and catalytic converter.
An important consideration in producing sulfur trioxide is maintaining the proper temperature and mass flow rates in the process to enhance efficiency. For example, the production rate of SO.sub.3 ought to be adjusted to correspond to the nature and volume of the exhaust gas to be treated. Furthermore, it is important to maintain the SO.sub.3 at a sufficiently high temperature to avoid condensation and formation of H.sub.2 SO.sub.4.
Known sulfur trioxide producing systems have used the temperature of gas entering a catalytic converter as a controlling variable that regulates the temperature of air entering a sulfur burner. A disadvantage with this type of control is the inability to control the temperature of gas leaving the catalytic converter. It is important to keep that temperature within a satisfactory range for the reasons given above. Also, the foregoing types of systems did not regulate according to the temperature of the air mass entering the sulfur burner. It is again important to regulate from this temperature to maintain efficient and safe operation.
Also, these known systems fail to feed-back important information about the operating parameters of the electrostatic precipitator and/or the exhaust gas associated therewith. For example, the flow rate of gas through an electrostatic precipitator can be an important variable which ought to be used to influence the production of SO.sub.3.
Accordingly, there is a need for an improved gas conditioning system for an electrostatic precipitator which is regulated to operate more efficiently.